The present invention relates generally to a lubricating system for an engine, and more specifically to a lubricating system which is fully automatic and lubricates an engine prior to start-up of the engine and prior to actuation of the oiling system built into the engine. The lubricating system is charged by the oiling system built into the engine when the engine is running and utilizes engine oil stored under pressure in a reservoir for lubricating the engine prior to the next start-up.
Factory fresh engines installed in vehicles have an oiling system which is operational only after the engine has been started. Consequently, during start-up of an engine which permits its lubricating oil to drain down and be collected in an oil pan there will be a period of time during which the internal components of the engine will be moving before they are lubricated again. The Society of Automotive Engineers have performed tests which indicate that 90 percent of the wear in an engine occurs during start-up, i.e., before the internal components are lubricated by the oiling system built into the engine.
There have been a number of inventors who have recognized the problem of dry starting an engine and attempted to provide for adequate lubrication during the critical period when the engine is being cranked just prior to start-up and prior to actuation of the oiling system built into the engine. A preoiling system, depicted in U.S. Pat. No. 2,736,307, includes a turbine driving a high pressure pump for charging a reservoir with engine oil which is released by engagement of the starter switch. Another type of preliminary lubricating system, depicted in U.S. Pat. Nos. 2,755,787 and 3,422,807, releases oil from a reservoir as the ignition is activated. A pre-oiler with a solenoid valve, which can also be manually actuated, is shown in U.S. Pat. No. 3,556,070. U.S. Pat. No. 3,583,525 shows a preliminary lubricating device having a solenoid attached to a valve piston shaft for controlling the flow of oil into and out of a reservoir. A valve arrangement, depicted in U.S. Pat. No. 3,583,527, controls the charge and discharge of a reservoir of oil, under pressure, in response to the closing of the ignition switch. Another engine preoiler, disclosed in U.S. Pat. No. 4,061,204, includes a valve arrangement in the base of an accumulator having multiple ports, some of which are closed in one position of the valve and some of which are always open. U.S. Pat. No. 4,094,293 depicts an engine pre-oiler with a reservoir for containing engine oil under pressure controlled by valve which in turn is controlled by the engine's oil pressure sensor unit. Yet another pre-lube device, depicted in U.S. Pat. No. 4,112,910, shows a holding mechanism for a coiled power spring which is released on actuation of the ignition system whereupon oil in a chamber is evacuated and used to lubricate an engine. Finally, a pre-lubrication system, depicted in U.S. Pat. No. 4,703,727, shows a high pressure oil pump, controlled by an ignition switch and an oil pressure sensor, for supplying oil to an engine prior to start-up.
Each of the above noted patents deals with the problem of dry start-up of an engine either in an ineffective manner or by way of complex and costly apparatus. Accordingly, there has continued to be a need for a lubricating system for the lubrication of an engine prior to start-up which is effective, simple, inexpensive to manufacture and which is easy to install on an existing engine without major modifications of the engine assembly.